The present invention relates to lithography in which light or X ray (hereinafter generically referred to as a "radiation") is used and particularly to X ray lithography by using graft copolymerization which advantageously exhibits a high throughput.
Hitherto, the exposure of a resist in lithography by making use of radiation-induced graft copolymerization has been limited to one carried out in vacuo or in an inactive gas, as described in, e.g., Appl. Phys. Lett., 44 (10), 15 May, 1984, p. 973-p. 975, and U.S. Pat. No. 4,195,108. The limitation was made in order to prevent a polymer radical of a resist produced through the exposure from being quenched due to the reaction thereof with an oxygen molecule.
In the above-described prior art, the exposure equipment should purposely be evacuated to produce a vacuum exposure atmosphere or should be provided with some means for replacing the atmosphere with an inactive gas. Further, the above-described control of the atmosphere raised a problem with respect to a lowering in the throughput of the lighography.